Before he killed at least four people in Britain's deadliest attack since the 2005 London bombings, Khalid Masood was considered by intelligence officers to be a criminal who posed little serious threat.
A Briton, Masood had shown up on the periphery of previous terrorism investigations that brought him to the attention of Britain's MI5 spy agency.
But the 52-year-old was not under investigation when he sped across Westminster Bridge on Wednesday, ploughing down pedestrians with a hired car before running into the parliamentary grounds and fatally stabbing an unarmed policeman.
He was shot dead by police.
Daesh claimed responsibility for Masood's attack, although it was unclear what links – if any – he had with the militant group. Police said there had been no prior intelligence about his intent to mount an attack.
Born Adrian Russell Ajao in Kent, to the southeast of London, on December 25, 1964, he moved several times before his most recent home in Birmingham in central England. He was a convert to Islam.
Known by a number of aliases, he racked up a string of convictions, but none for terrorism-related offences. His occupation was unclear.
It was as long ago as November 1983 that he first came to the attention of authorities when he was found guilty of causing criminal damage, while his last conviction came 14 years ago in December 2003 for possession of a knife.
"Our working assumption is that he was inspired by international terrorism," said Mark Rowley, Britain's senior counter-terrorism police officer.
Birmingham has been a hotbed for British radicals. One study published earlier this month says 39 of 269 people convicted in Britain of terrorism offences from 1998 to 2015 came from the city.
TRT World's Abubakr al Shamahi met members of the city's large Muslim community to find out how they have reacted to Masood's Birmingham links.
Prime Minister Theresa May on Thursday told parliament she believed Masood was inspired by what she called a warped Islamist ideology.
There are over 213,000 Muslims in Birmingham, making up over a fifth of the population, according to the 2011 census, and there has been growing concern about divisions in the diverse city.
Since the attack in London, police have raided a number of addresses across the city, arresting five men and two women on suspicion of preparing terrorist acts.
TRT World's Abubakr al Shamahi is in Birmingham where he spoke with one of Masood's neighbours.